This invention relates to a method for using friction and/or inertia welding to produce a welded assembly with a thin interlayer between two similar or dissimilar components, especially for use in automotive brake systems and other applications. The term xe2x80x9cfriction weldingxe2x80x9d as used in this description, is considered to include both direct drive friction welding as well as inertia welding.
In automotive brake systems, for example, it is necessary to manufacture a sleeve blank (for further machining) incorporating magnetic carbon steel material on each end with a thin layer of non-magnetic stainless steel between the magnetic materials. Other applications exist where bimetallic and tri-metallic assemblies are required with the interlayer material being very thin, compared to the length of the end pieces. It is required that the thin interlayer material thickness (after assembly) and position relative the end pieces be precisely controlled.
It is an object of the invention to provide a welded assembly which is easy to manufacture and which comprises bi-metallic or tri-metallic combinations of welded together components.
In the invention a method of welding an assembly, comprising two aligned cylindrical end pieces and an interposed transverse intermediate piece, utilizes friction welding to affix the end pieces to the intermediate piece.
The intermediate piece is held in a cavity of a holder during the welding operation. The intermediate piece is made from strip stock and has a non-round profile to form radially protruding ears, which contact the correspondingly shaped cavity in the holder.
The intermediate piece preferably has a base circle diameter which is sufficiently larger than the end piece diameter, to minimize the burnoff of the intermediate piece, and therefor precisely control the final thickness of the intermediate piece in the welded assembly.
Advantageously, one of the end pieces is friction welded to one side of the intermediate piece, and then the other of the end pieces is friction welded to the other side of the intermediate piece. Alternatively, the end pieces are friction welded to opposite sides of the intermediate piece simultaneously.
The end pieces are either tubular or solid bars, and the intermediate piece either has a central hole or is solid, depending upon the application of the assembly.